现象：

在用EM12cR4创建备库时，不能搜索到备库的主机，但备库主机已经在主机列表中存在，而且备库主机上的agent也已经安装并状态正常。

原因：

在agent端插件目录缺少所需要的插件

解决：

安装代理插件

1.  登录EM12c

2.  在菜单 安装-> Extensibility -Plug-ins> 

3.  在Plug-ins页，选择 Database -> Oracle Database

4.  点击 Deploy On -> Management Agent

5.  点Continue为列出的主机添加agent插件

参考文档：
12c Creation of Standby Database Failed with "The grid control database plug-in must be deployed on the agent monitoring the selected host." (文档 ID 1510979.1)

修改时间:2012-12-15类型:PROBLEM

In this Document

Enterprise Manager Base Platform - Version 12.1.0.2.0 to 12.1.0.2.0 [Release 12.1]
Information in this document applies to any platform.

Creation of Standby Database from OEM 12.1.0.2 fails with the following error:

The grid control database plug-in must be deployed on the agent monitoring the select host.

Plugins directory at the agent side does not have the required plugin

/u01/app/oracle/product/agent12c/plugins
$ ls -ltr
total 20
drwxr-xr-x 7 oracle oracle 4096 Nov 29 14:05 oracle.sysman.xa.discovery.plugin_12.1.0.3.0
drwxr-xr-x 7 oracle oracle 4096 Nov 29 14:05 oracle.sysman.oh.discovery.plugin_12.1.0.2.0
drwxr-xr-x 7 oracle oracle 4096 Nov 29 14:05 oracle.sysman.db.discovery.plugin_12.1.0.2.0
drwxr-xr-x 10 oracle oracle 4096 Nov 29 14:05 oracle.sysman.oh.agent.plugin_12.1.0.2.0
drwxr-xr-x 9 oracle oracle 4096 Nov 29 14:05 oracle.sysman.emas.discovery.plugin_12.1.0.3.0
 
oracle.sysman.db.agent.plugin is missing which is required for monitoring.
 

to create standby database on a new server, we still need a plugin to be deployed on the agent.

Please do the following steps:

1. Login to 12C Cloud Control
2. Navigate to Setup --> Extensibility
3. Select the option Plugins
4. Expand the option "Databases"
5. Select "Oracle Database"
6. Expand the option "Deploy On" and Choose "Management Agent"
7. In the page displayed, Click on "Add" to add the Agent on which plugin needs to be deployed (On the server where standby is created).
8. After adding the agent name, it will run the prerequisite check, after successful completion of prerequisite check, click on Next.
9. A Confirmation message about deployment of database plugin on Management Agent will be displayed.
 
This will complete the deployment of database plugin to management agent.

Once this is done, create standby database.